# How do you find

How do you find....

Im wondering whether how you find the speed of
a) space shuttle

and

b) submarines?

chroot
Staff Emeritus
Gold Member
The space shuttle must have a large enough tangential velocity to keep it in orbit. The velocity of a satellite in a circular orbit at a known altitude can be easily calculated:

http://hyperphysics.phy-astr.gsu.edu/hbase/orbv3.html

The velocity of a submarine, however, is up for grabs. The submarine could, of course, just stop and sit still.

The maximum speed that a submarine can reach will be the point where its engine output (in horsepower, for example) equals its losses due to hydrodynamic friction (drag). This assumes, of course, that the submarine's hull is capable of handling that kind of drag and so on. If you know the frontal area and drag coefficient of the sub, plus its maximum engine output, the top speed is also easy to calculate. You could probably look up the drag coefficient for a hemispherical front-end, which I believe most subs have. These kinds of things are difficult to calculate accurately without a lot of very specific, detailed measurements.

http://hyperphysics.phy-astr.gsu.edu/hbase/airfri2.html#c2

- Warren

ok. I see...
If such speed is attainable, so how does technology achieve such speed?

LURCH